First post here. I've scoured this forum for a solution to my problem but can't find any threads with this particular issue. Truck is a 98 model with push button 4wd. NP 243 C t-case. When I try to engage 4HI or 4LO, I hear relays clicking and I sometimes get a clunk from the transfer case, the lights flash a couple times, but then it reverts back to 2HI. Here's what I have done so far. I checked the TCCM for codes and only get DTC 1. I assume that's from all my battery disconnecting and fuse removal. (edit - I cycled the ignition switch 5 times and got rid of this code, so now there are no trouble codes.) I replaced the switch on the top of the transfer case since it was a cheap and easy part. That didn't help. Here's where things get strange. I then replaced the encoder motor on the t-case. When I got the new motor, the paperwork said that it was shipped in the 2HI position and that if my transfer case wasn't in 2HI I would have to manually shift it to get the tang to align. Well, this motor was in the 4HI position, and even had a plastic keeper "holding" it there (although I can't see how it could move on its own). So I shifted the t-case to 4HI with a crescent wrench and installed the motor. When I turned the key on, the light on the 4HI dash switch was lit and I thought great, I should be good to go. Well, then the t-case shifted beautifully between 4HI and 4LO, the actuator engaged the front differential and everything worked great EXCEPT now I couldn't shift out of 4WD to 2HI. Another issue was when in 4HI, when I shifted to reverse, I got a grinding noise from the t-case. What I found when I pulled this motor back off was that when in 4HI it had the tang on the t-case turned a few degrees toward 4LO so I assume that's why it was grinding. Also, the plastic keeper it was shipped with wouldn't align anymore. So, I got a reman'd Delco encoder motor. This one was in fact shipped in the 2HI position. I installed it and still had the original issue. Won't shift out of 2HI. The last thing I did was try a new TCCM and that didn't help. Same issue. Any more ideas? I've basically tested/replaced every electronic component I know of in the 4WD system except the dash switches. I assume the switches are OK because I hear relays clicking and lights are flashing. Is this a bad assumption?